Comparative Perfusion Analysis of Free Muscle-Sparing Versus Pedicle Transverse Rectus Abdominis Myocutaneous (TRAM) Flaps in Vivo in the Peri-Operative and Late Post-Operative Periods

BACKGROUND Current teaching suggests increased perfusion in free transverse rectus abdominis myocutaneous (TRAM) flaps over pedicled TRAM flaps, broadening indications for its use in high risk patients. This study compared perfusion analysis of free muscle-sparing versus pedicle TRAM flaps in vivo in the peri-operative and late post-operative periods. METHODS The SPY-Elite system using indocyanine green dye was used to analyze flap perfusion intra-operatively and at 1 week and 3 months post-operatively. Image analysis was completed by evaluating the perfusion maps from the SPY- Elite system with Image J software calculate maximum, minimum, and average luminescence over the surface area of the flaps. Student's T-test was used for statistical analysis. RESULTS Intra-operatively, we found a 73.4% greater perfusion in the free muscle-sparing as compared to the pedicled TRAM. This increase in free muscle-sparing TRAM perfusion was not evident 1 week post-operatively, due to a relative increase in pedicle flap perfusion that coincided with a revision of the pedicled flap due to distal flap necrosis. At 3 months, the free muscle-sparing TRAM flap once again showed superior perfusion with a 15.7% increase over the pedicled flap. CONCLUSION We showed superior free muscle-sparing TRAM perfusion in the early peri-operative period which coincided with the time framein which flap loss was most common. Local swelling, pedicle rotation, tunneling, and dominance of the deep inferior epigastric circulation were potential causes of initial decreased pedicled TRAM perfusion. This analysis adds more objective data to the question of indications and relative strengths between free and pedicled TRAM flaps.